That logic is bogus. The heat generated by electrical resistance is very inefficient. Also, the heat is only a positive in northern climes, the heat is a negative during A/C usage, and that is where much of the electrical usage goes.

The question is: How much will the consumer save by converting to LED lights with equal light output but with 150 lm/W efficiency? The answer may surprise you because the answer is ZERO. Why zero?

This is only true if the house has direct electric resistance heating. My house has a heat-pump, so it costs maybe 20% as much electricity to provide the same amount of heat as a resistance heater (like a light-bulb or an electric baseboard heater).

Also, in the summer, the air conditioner doesn't have to remove as much heat from the house when I run CFLs. The heating effect of incandescent light-bulbs is quite noticeable; the heat-pump air conditioning system went out in my girlfriend's apartment last summer, and we made the temperatures bearable by switching her incandescent bulbs to CFLs. (Plus, it gave us something to do.)

So, sorry, your blanket statement is wrong. In houses that only feature electric resistance heat, you're right -- but you're just plain wrong wrong for houses that have heat-pumps, oil-heat, wood-heat, district-steam heating, solar hot-water hydronic heating, or any other kind of heating system.

What Luke says is true, the effect in the summer of reducing the cooling load easily makes up for the loss from heating in the winter, and is especially true for those who don't have electric heating, which is the least efficent way of producing heat. Suposedly the thermodynamic efficency of electricity is only about 10% by the time it gets to your house, evey 1 unit of energy you save in the home saves 10 units of energy throughout the system.

Hmm on #1 you forgot about summer....... how about all the waste heat NOT generated by cfl's and led's during summer that you dont need extra a/c to compensate for ......this is really irresponsible reporting

If you live in Alaska, by all means use incandescent, you have my blessing.

What Luke says is true, the effect in the summer of reducing the cooling load easily makes up for the loss from heating in the winter,

That's not quite what I said. I said that in my house, CFLs are more efficient in both the summer and in the winter because my house is heated/cooled by a heat-pump.

For instance, if I run a 100W light builb all day (12 hours), it will use 100W*12hrs = 1.2 KWh and deliver about 1.2 KWh *3412 BTU/KWh - 4095 BTU of heat into the house. The author is correct that this calculation is exactly the same for an electric baseboard heater -- and for all I know, that may be the heating system that he has in his house.

However, for my house, if I deliver that same amount of heat to my house through my heat-pump, I use many times less energy to do so. (I said 20% above, which wasn't quite right -- 33% is closer, according to http://en.wikipedia.org/wiki/Heat_pump#Efficiency -- but it depends a great deal on the ambient temperature.) So, with my heat-pump, I use about 0.4 KWh to deliver that same 4095 BTU! But, now I need a light -- let's assume (incorrectly) that my CFL produces no heat. A typical 100 watt-equivelent CFL uses about 23 watts of electricity, so the bulb uses about 0.3 KWh. So, now, my heat-pump + CFL system is using 0.7KWh instead of 1.2KWh -- so it's nearly twice as efficient. In real life the heat-pump + CFL system would be a great deal more efficient, since I can't heat my house with just the 100W light bulbs!

Oh, as your for 90% loss from electricity, I must disagree. Those steam turbines are pretty efficient; they're pretty darned close to that 60% thermodynamic limit, and the transmission losses are more like 10%-15%, so the real-life efficiency of heating with electricity is close to 50%. My university uses the waste-heat from their power-plant to power a steam district-heating system (known as combined heating and power), so the numbers are much better in the winter.

The reality of having new technology helping society and environment is great! Everybody starts small.

I'll recap what I stated on the forums.

A) Most of your lights are in the ceiling. This means all the heat generated never reaches you. It goes up.

B) The argument presented is applicable ONLY for non-tropical regions ONLY about 4 months out of the year for what little heat is generated from the lightbulbs that gets to you.

C) Heat does not transfer well AT ALL (It's a great insulator for that reason). The heat stays at the bulb anyway.

D) The only thing this really does is bring up the fact that we are _slightly_ overestimating our savings. But just barely.

I appreciate discussion, but please don't trumpet what this guy stated as fact. It's horrible for this green site to be trumpeting us to stay with incandescents.

In brighter news, I found a site on stumbleupon (google it, I'm sure it'll come up) that presents plasma bulbs that get twice as many lumens as even LEDs per watt. The lightbulb of the future is around the corner. There's even a flash video of this tiny bulb that gives off tremendous light. It's pretty cool.

Ditto to Dan, Luke and Buzz saw (Peter Paul and Manson? Could be a good band name).

Any utility (even in Vermont where I live) will tell you that air conditioning has become the greatest use of electricity. Power production can actually fall in the winter because hardly anyone uses inefficient and costly electric resistance heaters anymore.

I've replaced the lights in my room with LEDs and in the last year I haven't once burned my hand on my metal desk lamp. I've also replaced the lights in my fridge and freezer because I figure I get a double benefit by eliminating heat sources in an area I'm trying to keep under 40 degrees. I got everything at www.ledlight.com, which seems to have the best prices and the most product diversity online.

LEDs also last much much longer so there is less shipping, packaging and waste disposal involved.